Grooved valve seat with inlay

ABSTRACT

A valve seat includes a seat body with an inlay and at least one groove. The seat body has a passage which extends from a first opening to a second opening in the seat body. A channel is located in the seat body adjacent the first opening and extends around at least a portion of the passage. The inlay is located in at least a portion of the channel. The groove extends along at least a portion of an inner surface of the passage from the first opening towards the second opening.

FIELD OF THE INVENTION

[0001] This invention relates generally to valve seats and, moreparticularly, to a valve seat with an inlay and grooves for use in amachine, such as a turbine.

BACKGROUND OF THE INVENTION

[0002] In variety of different applications, such as in a steam turbine,it is important to be able to control the flow of a motive fluid, suchas steam, through the machine. To achieve this control, theseapplications typically employ the use of a valve assembly. Each of thevalve assemblies is located in a passage in the machine and includes astopper which can be moved between an open position exposing an openingto the passage and a closed position sealing the opening to the passage.To help form a seal between the passage and the stopper, the valveassemblies sometimes include a valve seat which is located in thepassage and has a narrower passage.

[0003] Although the valve seat is helpful in forming a seal with thevalve stopper, there are some problems with existing valve seats. Forexample, one problem with these valve seats is that over time the valveseats begin to corrode and/or erode away, particularly near the portionof the valve seat which engages with the valve stopper due to highvelocities. As a result, the seal formed between the valve stopper andthe valve seat often begins to deteriorate permitting motive fluid toleak through the fluid passage when the valve stopper is in a closedposition.

[0004] Another problem with these existing valve seats is that the valveseats are not designed to control the flow of motive fluid in a laminarflow through the fluid passage.

[0005] Yet another problem with these and existing valve seats is thatthey can not handle higher velocity flow, e.g. flow at rates above 600feet/second when the valve stopper is operating close to the valve seat.

SUMMARY OF THE INVENTION

[0006] A valve seat in accordance with one embodiment of the presentinvention includes a seat body with a channel and an inlay. The seatbody has a passage which extends from a first opening to a secondopening in the seat body. The channel is located in the seat bodyadjacent the first opening and extends around at least a portion of thepassage. The inlay is located in at least a portion of the channel.

[0007] A valve seat in accordance with another embodiment of the presentinvention includes a seat body with at least one groove. The seat bodyhas a passage which extends from a first opening to a second opening inthe seat body. The groove extends along at least a portion of an innersurface of the passage from the first opening towards the secondopening.

[0008] A machine in accordance with another embodiment of the presentinvention includes a housing with a fluid passage, a seat body with achannel and an inlay, and a valve stopper. The seat body is seated inthe fluid passage in the housing and has its own fluid passage whichextends from a first opening to a second opening in the seat body. Thechannel is located in the seat body adjacent the first opening andextends around at least a portion of the fluid passage in the seat body.The inlay is located in at least a portion of the channel. The valvestopper is moveable between a first position sealing against the firstopening and at least a portion of the inlay of the seat body and asecond position exposing the first opening.

[0009] A machine in accordance with another embodiment of the presentinvention includes a housing with a fluid passage, a seat body with atleast one groove, and a valve stopper. The seat body is seated in thefluid passage in the housing and has its own fluid passage which extendsfrom a first opening to a second opening in the seat body, the seatbody. The groove extends along at least a portion of an inner surface ofthe passage from the first opening towards the second opening. The valvestopper is moveable between a first position sealing against the firstopening of the seat body and a second position exposing the firstopening.

[0010] With present invention the inlay in the channel or grooveadjacent the first opening to the valve seat reduces the effects ofcorrosion and/or erosion to the valve seat. As a result, when the valvestopper is pressed against the valve seat to seal the first opening, theinlay helps to maintain the integrity of the portion of the valve seatnear the first opening which seals against the valve stopper and thuspermitting a seal to be achieved and maintained.

[0011] Additionally, with the present invention the corners or sharpedges of the grooves which extend along the fluid passage in the valveseat from the first opening towards the second opening in the valve seatredirect the flow pattern to cause laminarization of the motive fluid.More specifically, the grooves reduce the velocity of the motive fluidpassing through the valve seat. The geometry of the grooves reduces thecyclonic effect inherent to fluids passing through an orifice orpassage. The additional area provided by the grooves also allows forvolumetric expansion of the motive fluid into this area which reducesthe effects of the minor venturi caused from the geometry when the valvestopper is in close proximity to the first opening to the valve seat.

[0012] Further, by tapering the interior seat wall or surface of thepassage from the first opening to the second opening in the valve seatand including the grooves along the inner surface of the fluid passage,a venturi effect is created which decreases the losses due to frictionof the motive fluid passing through the valve seat because the groovesreduce the turbulence.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a cross-sectional view of a valve seat in accordancewith one embodiment of the present invention in a motive fluid supplychamber of a turbine;

[0014]FIG. 2A is a cross-sectional view of a valve seat in accordancewith another embodiment of the present invention (for ease ofillustration the grooves along an inner surface of a fluid passage inthe valve seat are not shown in this view);

[0015]FIG. 2B is an enlarged view of a circled portion of the valve seatshown in FIG. 2A which illustrates a channel without the inlay;

[0016]FIG. 2C is a cross-sectional view of the valve seat shown in FIG.2A taken along lines 2C-2C (this cross-sectional view illustrates theentire valve seat, although only a portion of the valve seat is shown inthe cross-sectional view shown in FIG. 2A; and

[0017]FIG. 2D is a cross-sectional view of the valve seat shown in FIG.2A with the valve stopper sealing the first opening and with one of thegrooves along the inner surface of the fluid passage in the valve seatillustrated (for ease of illustration the other grooves are not shown inthis view).

DETAILED DESCRIPTION

[0018] A valve seat 10 in accordance with one embodiment of the presentinvention is illustrated in FIGS. 1 and 2A-2D. The valve seat 10includes a seat body 12 having a passage 14 which extends from a firstopening 16 to a second opening 18 in the seat body 12, an inlay 20located in a channel 22 in the seat body 12 adjacent the first opening16 and which extends around at least a portion of the passage 14, and agroove 24 that extends along at least a portion of an inner surface 26of the passage 14 from the first opening 16 towards the second opening18. The present invention provides a number of advantages includingreducing the effects of corrosion and/or erosion to the valve seat 10with the inlay 20 in the channel 22. Additionally, the present inventioncauses laminarization of the motive fluid and provides an additionalarea for volumetric expansion in the valve seat 10 with the grooves 24.

[0019] Referring to FIG. 1, a cross-sectional view of a motive supplychamber or motive fluid chest 28 of a turbine 30 is illustrated. Sincethe components and operation of a turbine 30 are well known to those ofordinary skill in the art, they will not be discussed in detail here. Byway of example, the components and operation of a turbine 30 aredisclosed in U.S. Pat. No. 5,927,943 to Maier for an Inlet Casing for aTurbine which is herein incorporated by reference. Although in thisparticular embodiment, the valve seat 10 is shown in a fluid passage 32in a turbine 30, the valve seat 10 can be used anywhere in any type ofmachine to help control the flow of a motive fluid, such as steam.

[0020] The motive fluid supply chamber 28 includes a housing or a casing34 with an inlet chamber 36 and a plurality of fluid passages 32. Thefluid passages 32 each have an inlet 38 connected to the inlet chamber36 and an outlet 40 which in this particular example feeds into nozzlesfor the turbine 10. A motive fluid, such as steam, is supplied to theinlet chamber 36 and passes through the fluid passages 32 from theinlets 38 to the outlets 40.

[0021] A control valve assembly 42 is mounted in the housing 34 aboveeach of the fluid passages 32. Since the components and operation ofcontrol valve assemblies 42 are well known to those of ordinary skill inthe art they will not be discussed in detail here. One example of acontrol valve assembly 42 and its operation is disclosed in U.S. Pat.No. 5,277,403 to Waggott et al. for a Balanced, Steam Control ValveAssembly and a Plug-Type Valving Element which is herein incorporated byreference.

[0022] In this particular embodiment, each control valve assembly 42includes a stem 44 which is connected at one end to the valve stopper 46and adjacent an opposing end to a bonnet 48. An actuating system (notshown) can move the valve stopper 46 with the stem 44 from a firstposition seated against the first opening 16 to the valve seat 10 toother open positions exposing the first opening 16 in the valve seat 10.The actuating system can control the amount of flow passing into thepassage 14 through the first opening 16 by controlling the distance thatthe valve stopper 46 is pulled away from the first opening 16 to thevalve seat 10. Although in this particular embodiment, each valvestopper 46 and stem 44 has a different actuating system, a singleactuating system can be used to control the movement of all of the valvestoppers 46 and stems 44 if needed or desired.

[0023] Referring to FIGS. 1 and 2A-2D, a valve seat 10 is disposed orseated in each of the fluid passages 32. The outer surface 50 of thevalve seat 10 is designed to fit snugly against the inner surface 31 ofthe fluid passage 32 with an interference fit to hold the valve seat 10in place. In this particular embodiment, the valve seat 10 has asubstantially circular cross-sectional shape which mates with thesubstantially circular cross-sectional shape of the fluid passage 32,although the cross-sectional shapes of the fluid passage 32 and the seatvalve 10 can vary as long as the two can mate and substantially preventthe leakage of motive fluid between the two. Additionally, in thisparticular embodiment the valve seat 10 includes a lip 52 adjacent tothe first opening 16 of the valve seat 10 which extends away from thevalve seat 10 and includes a thermal expansion slot. The lip 52 helps toform the seal against the inlet 38 to the fluid passage 32 in thehousing 34. The valve seat 10 can be made from a variety of differentmaterials, such as a material which is one-and-one-half Cr and one halfMo or 410 to 416L Stainless Steel.

[0024] The valve seat 10 has a fluid passage 14 which extends from afirst seat opening 16 to a second seat opening 18. When the valve seat10 is seated in the fluid passage 32, the fluid passage 14 extends alongand permits the flow of motive fluid in the same general direction asthe fluid passage 32 permitted. In this particular embodiment, the fluidpassage 14 in the valve seat 10 tapers between the first seat opening 16and the second seat opening 18 as shown in FIGS. 1 and 2A, although thedirection and amount, if any, of taper in the fluid passage 14 can varyas needed or desired. In this particular example, the first seat opening16 has a smaller inner periphery than the second seat opening 18 as aresult of the taper in the fluid passage 14. By tapering the fluidpassage 14 in the valve seat 10, the valve seat 10 can function as anozzle and can decrease the losses due to friction of the motive fluidpassing through the fluid passage 14. In this particular embodiment, thetaper from a throat portion 51 of the fluid passage 14 is about fivedegrees and thirty minutes, which is the preferred taper, although otherdegrees of taper can be used.

[0025] Referring to FIGS. 1, 2A, 2B, and 2D, a channel or groove 22 isformed along an inner edge 54 of the valve seat 10 adjacent to the firstopening 16. In this particular embodiment, the channel 22 extends aroundthe entire periphery of the inner edge 54 of the valve seat 10 adjacentto the first opening 16, although other configurations can be used, suchas having the channel 22 extend only part of the way around the firstseat opening 16 to the fluid passage 14 or having a plurality ofdiscontinuous, channels spaced around the periphery of the valve seat 10near the inner edge 54. An enlarged cross-sectional view of the channel22 for the inlay 20 in this particular embodiment is shown in FIG. 2B.The particular shape of the channel 22 can vary as needed or desired.The channel 22 should have a sufficient shape and depth to be able toretain an inlay 20.

[0026] Referring to FIGS. 1 and 2A, in this particular embodiment aninlay 20 is disposed in and substantially all of the way around thechannel 22 and is used to form a seal with the valve stopper 46,although other configurations for placing the inlay 20 in the channel 22can be used, such as only partially filling the channel 22. Additionallyin this particular embodiment, the inlay 20 is a material, such asStellite which is a nickel cobalt alloy manufactured by the HaynesStellite Co., although other types of materials, such as tungsten, canalso be used. When the valve stopper 46 is moved to a sealing or closedposition, the valve stopper 46 rests against the inlay 20 in the channel22. The inlay 20 helps to reduce the effects of corrosion and erosiontypically experienced by a valve seat 10 over time and thus helps tomaintain a tight seal between the valve stopper 46 and the inner edge 54of the valve seat 10 when the valve stopper 46 is in a closed position.

[0027] Referring to FIG. 2C, in this particular embodiment a pluralityof grooves 24 are located along an inner surface 26 of the fluid passage14 which each extend from adjacent the first seat opening 16 towards butdo not reach the second seat opening 20 at one end of valve seat 10 andare spaced an equal distant apart in the fluid passage 14, although thenumber of grooves 24, if any, as well as their location, length in thefluid passage 14, and spacing at equal or different distances can varyas needed or desired. In this particular example, the valve seat 10 haseight grooves 24 formed in the inner surface 26 of the fluid passage 14of the valve seat 10 which are spaced an equal distance apart and extenddown along a portion of the inner surface 26. The grooves 24 help toredirect the flow pattern to cause laminarization of the motive fluidpassing through the fluid passage 14. The grooves 24 also provide roomfor volumetric expansion of the motive fluid in the fluid passage 14which helps to reduce the minor venturi effect caused by the geometry ofthe valve seat 10 and the valve stopper 46 when the valve stopper 46 hasbeen moved away from, but is still in close proximity to the first seatopening 16 to the valve seat 10. In this particular embodiment, thegrooves 24 also have a substantially rectangular cross-sectional shapewhich has sharp edges or corners 56, although the grooves 24 can haveother shapes and/or more rounded edges. Preferably, the shape selectedfor the grooves 24 has at least one sharp edge and/or corner 56 becausethe sharp edges and/or corners also help redirect the flow pattern forthe motive fluid and to cause laminarization of the motive fluid.

[0028] The operation of the valve seat 10 will be illustrated withreference to FIGS. 1, 2A and 2C with reference to the fluid passage 32in the motive fluid supply chamber 28 of a turbine 30, although thevalve seat 10 can be used anywhere to help control the flow through afluid passage 32. In this particular example, motive fluid, such assteam, will be supplied to the inlet chamber 36. The valve stoppers 46will be seated against the inner edge 54 with the inlay 20 in the valveseat 10 adjacent the first opening 16. As discussed earlier, the inlay20 reduces the effects of corrosion and erosion that typically occursalong the inner edge 54 of the valve seat 10 over time and can result inleakage of motive fluid into the fluid passage 14 past the valve stopper46.

[0029] At an appropriate time based upon the particular application, oneor more of the actuating systems are engaged to lift the stems 44 andthus the valve stoppers 46 off of the inner edge 54 of the valve seat 10adjacent the first opening 16 to permit the motive fluid to enter thefluid passage 14. The distance that the valve stopper 46 is raised fromthe first opening 16 effects the amount and rate at which the motivefluid enters the fluid passage 14. When the valve stopper 46 is still inclose proximity to the first opening 16 to the valve seat 10, a minorventuri effect may be caused. The grooves 24 in the valve seat 10 permitvolumetric expansion of the motive fluid as it enters the fluid passage14 which helps to reduce this venturi effect.

[0030] When the valve stopper 46 is moved away from the first opening 16to the fluid passage 14, the motive fluid passes through the fluidpassage 14 from the first opening 16 to the second opening 18. With thetaper in the fluid passage 14 between the first and second openings 16and 18, the valve seat 10 functions as a nozzle and the taper causes aventuri effect thus reducing the losses due to friction as the motivefluid passes through the fluid passage 14. The grooves 24 in the innersurface 26 of the fluid passage 14 help to redirect the flow pattern ofthe motive fluid to cause laminarization of the fluid flow through thefluid passage 14. Additionally, the sharp edges and/or corners 56 in theshape of the grooves 24 help with the redirection of the fluid flow tocause laminarization of the motive fluid. The size, number, and spacingof the grooves 24 can be selected to generate a particular direction offlow for the motive fluid as it exits the valve seat 10.

[0031] Having thus described the basic concept of the invention, it willbe rather apparent to those skilled in the art that the foregoingdetailed disclosure is intended to be presented by way of example only,and is not limiting. Various alternations, improvements, andmodifications will occur and are intended to those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested hereby, and are within thespirit and scope of the invention. Accordingly, the invention is limitedonly by the following claims and equivalents thereto.

What is claimed is:
 1. A valve seat comprising: a seat body having apassage which extends from a first opening to a second opening in theseat body; a channel formed in the seat body adjacent the first opening,the channel extending around at least a portion of the passage; and aninlay located in at least a portion of the channel.
 2. The valve seat asset forth in claim 1 wherein the channel and the inlay extend all theway around the passage.
 3. The valve seat as set forth in claim 1wherein the passage in the seat body tapers between the first openingand the second opening.
 4. The valve seat as set forth in claim 3wherein the taper is about five degrees and thirty minutes from a throatportion of the passage.
 5. The valve seat as set forth in claim 1wherein the inlay is made of at least one metal material.
 6. The valveseat as set forth in claim 1 further comprising at least one groovewhich extends along at least a portion of an inner surface of thepassage from the first opening towards the second opening.
 7. The valveseat as set forth in claim 6 wherein the groove extends from the firstopening to the second opening in the passage.
 8. The valve seat as setforth in claim 6 wherein the groove has at least one corner.
 9. Thevalve seat as set forth in claim 1 wherein there are a plurality grooveswhich extend along at least a portion of an inner surface of the passagefrom the first opening towards the second opening and which are spaced asubstantially equal distance apart around an inner surface of thepassage.
 10. A valve seat comprising: a seat body having a passage whichextends from a first opening to a second opening in the seat body; andat least one groove which extends along at least a portion of an innersurface of the passage from the first opening towards the secondopening.
 11. The valve seat as set forth in claim 10 wherein the grooveextends from the first opening to the second opening in the passage. 12.The valve seat as set forth in claim 10 wherein the groove has at leastone comer.
 13. The valve seat as set forth in claim 10 wherein there area plurality grooves which extend along at least a portion of an innersurface of the passage from the first opening towards the second openingand which are spaced a substantially equal distance apart around aninner surface of the passage.
 14. A machine comprising: a housing; afirst fluid passage in the housing; a seat body having a second fluidpassage which extends from a first opening to a second opening in theseat body, the seat body fitted in the first fluid passage; a channellocated in the seat body adjacent the first opening, the channelextending around at least a portion of the second fluid passage in theseat body; an inlay located in at least a portion of the channel; and astopper moveable from a first position sealing against the first openingand at least a portion of the inlay of the seat body and a secondposition exposing the first opening.
 15. The turbine as set forth inclaim 14 wherein the channel and the inlay extend all the way around thesecond fluid passage.
 16. The turbine as set forth in claim 14 whereinthe second fluid passage in the seat body tapers between the firstopening and the second opening.
 17. The turbine as set forth in claim 16wherein the taper is about five degrees and thirty minutes from a throatportion of the passage.
 18. The turbine as set forth in claim 14 whereinthe inlay is made of at least one metal material.
 19. The turbine as setforth in claim 14 further comprising at least one groove which extendsalong at least a portion of the second fluid passage from the firstopening towards the second opening.
 20. The turbine as set forth inclaim 19 wherein the groove extends from the first opening to the secondopening in the second fluid passage.
 21. The turbine as set forth inclaim 19 wherein the groove has at least one corner.
 22. The turbine asset forth in claim 14 wherein there are a plurality grooves which extendalong at least a portion of an inner surface of the passage from thefirst opening towards the second opening and which are spaced asubstantially equal distance apart around an inner surface of thepassage.
 23. A machine comprising: a housing; a first fluid passage inthe housing; a seat body having a passage which extends from a firstopening to a second opening in the seat body, the seat body seated inthe first fluid passage; at least one groove which extends along atleast a portion of an inner surface of the passage from the firstopening towards the second opening; and a stopper moveable between afirst position sealing against the first opening of the seat body and asecond position exposing the first opening.
 24. The turbine as set forthin claim 23 wherein the groove extends from the first opening to thesecond opening in the second fluid passage.
 25. The turbine as set forthin claim 23 wherein the groove has at least one corner.
 26. The turbineas set forth in claim 23 wherein there are a plurality grooves whichextend along at least a portion of an inner surface of the passage fromthe first opening towards the second opening and which are spaced asubstantially equal distance apart around an inner surface of thepassage.